1. Order of Ushakov - to naval commanders for meritorious service.
2. Medal for Military Valour Class 2
Not sure about the rest yet, will have to dig a bit!
Your man was perhaps a Naval Attaché... so a serving naval officer in a diplomatic posting.

This is all fascinating and informative, as I'm working on the Venezuela section of my website at the moment!
Just to add even more confusion, it appears that the entire thing was dropped and replaced in 2010 by the Orden Libertadores y Libertadoras de Venezuela in collar and 3 classes - and a quite different centrepiece to the badge, if a rather scruffy image in the Spanish version of Wikipedia is to be believed. No idea as to the design of the stars worn by Class 1 and Class 2, yet. The ribbon is yellow/blue/red with small white stars on the blue stripe.
I have found the law creating it, In Spanish of course, and am struggling my way through a translation (my Spanish is at the 'May I have a beer, please?' and 'Where is the bathroom?' level!). If anyone's good at Spanish I can send a copy over, she says hopefully...
I have found an image from earlier this year of a 100-year old musician called Juan Vicente Torrealba receiving the Class 1 of the order - you can see the stars on the sash and the star but it is not at all clear.

Guyana became independent from the UK in 1966, but did not institute her own orders until becoming a Republic in 1970. The highest order, awarded in a single class, is the Order of Excellence of Guyana. It is awarded to up to 25 living citizens of the Republic for distinction and eminence in any field of endeavour of national or international importance. Foreigners may receive honorary awards. Badge: Star:

Maarjamaa Risti teenetemärk
Instituted in 1995 and awarded to Estonians and foreigners for services to the state in 6 classes.
Here is the Collar, which with a star makes up a 'special' class.
Obverse:
Reverse:

The Greek is basically the title of each medal
Διασυμμαχικόν Μετάλλιον Νίκης = Allied Victory Medal
Πολεμικός Σταυρός = War Cross (3rd Class)
Αριστείον Ανδρείας = literally 'Award for Bravery', usually called the Cross of Valour.

All Vietnam-era, bottom 2 are US.
Top: Unknown, probably one of the 'joke' patches that were made up in country and worn unofficially.
Middle: (blue with wing) is 173rd Airborne Brigade Combat Team (normally seen with a white on blue AIRBORNE arc above).
Bottom: (red with sword) is US Military Assistance Command Vietnam.

Boris, if you ever need any 'raw materials' medal images, please ask - you'd be welcome to the source images I have here on my hard drive.
I use PaintShop Pro for image handling. I had a play yesterday and I have identified a quicker method for making images for my website than hitherto (but only when done on a large original and then reduced, it still needs extra work if I want the full-size image on a black background for something!).

You do beautiful work, Boris.
How do you prepare the medal images to put them on the background of your choice? That's the thing that slows me down, putting them on a black background for my website. I'd love to have a better way that adding the black by hand!

Thank you, Emmanuel, for sharing fascinating images of rarely-seen medals.
As for the somewhat ungentlemanly bickering, all I can say from my own experience is that storekeepers can often been quite reluctant to hand out the stuff you ARE entitled to, never mind anything else